How do I disable the Laptop's Display

Hi guys,
Recently I bought external LCD display for my old compaq nx9010 so that my daughter can use it. This laptop is with ATI card. It has shared memory of 64mb out of 512 so at times its very very slow. Is there anyway to disable to laptop's default display and display everything on external display?
Thanks a lot in advance
Girish

Most, but not all laptops all the connection of an external display. This may enable the user to switch to a new external display automatically. Others may require you to press a sequence of keys. Common series are one or more of the following:
Fn +F9
Fn +F8
Fn +F5
Fn +F3

Or look for a little image near the output socket for pressing CRT or LCD with a drawing of a monitor on a key on the keyboard.
This varies even among different models by the same manufacturer.
Consult your laptop documentation, or the tech support site for that brand and model. The possibilities exist or they would not have the external socket.
Check also the CMOS setup, or the BIOS.
Check the documentation that come with your display drivers as well.
Be sure the external monitor is detected by the BIOS before you get too far along. If it is not detected, not further work is going to pay off.
If you wish to change the external display's resolution, make sure the monitor is detected by the operating system or posted in the BIOS. You can also search for this monitor detection by going to the Device Manager in Hardware of System.

you are spot on. Yes Fn + F8 key is there and similar combination works for my other laptop. Ufortunately keyboard for this perticular laptop is totally broken so I use USB keyboard. and this keyboard has no function key. Now how do I do that?
Thanks a lot
Girish